The present invention relates to a malfunction detecting device for detecting an open circuit condition at an output terminal of a generator such as a vehicle-mounted DC generator driven by an engine.
If the output terminal of a DC generator is open circuited, the battery cannot be charged by the generator. If the vehicle is continuously driven under such a condition, the battery will be discharged to the point that the engine cannot be started.
Moreover, if the positive battery cable is grounded for any reason, the cable may burn out and there is a danger of fire.
In order to avoid these problems, the open-circuit state of the DC generator output terminal must first be detected. However, there has been no reliable detection device for performing this function previously available.